Influence of Milk-Feeding Type and Genetic Risk of Developing Coeliac Disease on Intestinal Microbiota of Infants: The PROFICEL Study

Abstract

Interactions between environmental factors and predisposing genes could be involved in the development of coeliac disease (CD). This study has assessed whether milk-feeding type and HLA-genotype influence the intestinal microbiota composition of infants with a family history of CD. The study included 164 healthy newborns, with at least one first-degree relative with CD, classified according to their HLA-DQ genotype by PCR-SSP DQB1 and DQA1 typing. Faecal microbiota was analysed by quantitative PCR at 7 days, and at 1 and 4 months of age. Significant interactions between milk-feeding type and HLA-DQ genotype on bacterial numbers were not detected by applying a linear mixed-model analysis for repeated measures. In the whole population, breast-feeding promoted colonization of C. leptum group, B. longum and B. breve, while formula-feeding promoted that of Bacteroides fragilis group, C. coccoides-E. rectale group, E. coli and B. lactis. Moreover, increased numbers of B. fragilis group and Staphylococcus spp., and reduced numbers of Bifidobacterium spp. and B. longum were detected in infants with increased genetic risk of developing CD. Analyses within subgroups of either breast-fed or formula-fed infants indicated that in both cases increased risk of CD was associated with lower numbers of B. longum and/or Bifidobacterium spp. In addition, in breast-fed infants the increased genetic risk of developing CD was associated with increased C. leptum group numbers, while in formula-fed infants it was associated with increased Staphylococcus and B. fragilis group numbers. Overall, milk-feeding type in conjunction with HLA-DQ genotype play a role in establishing infants' gut microbiota; moreover, breast-feeding reduced the genotype-related differences in microbiota composition, which could partly explain the protective role attributed to breast milk in this disorder.

Increased prevalence of pathogenic bacteria in the gut microbiota of infants at risk of developing celiac disease: The PROFICEL study

“…7 Here, using species-specific primers, we have analysed the prevalence of two potentially pathogenic species of the Clostridium genus. The increased prevalence of C. perfringens found at 7 days, 1 month and 4 months of age in the formula-fed infants of our cohort is in agreement with previous studies reporting that formula feeding promoted the presence of C. perfringens .…”

“…7 , 8 In particular, we described that breast-fed infants with a high genetic risk (HLA-DQ2) of developing CD had reductions in Bifidobacterium spp., a feature that theoretically could be related to the development of the disease in the later life. 7 , 8 Besides, we observed that infants with a high genetic risk (HLA-DQ2) had a higher relative abundance of Proteobacteria, and of unclassified Enterobacteriaceae. 8 However, all the preceding studies were taxonomy-based, and the pathogenic potential of the increased abundance of the family Enterobacteriaceae remained unexplored.…”

“…8 Then, it can be hypothesized that the higher prevalence of C. perfringens and C. difficile , and of enterotoxigenic E. coli might be a consequence of the reductions in Bifidobacterium numbers as previously observed in formula-fed infants and the carriers of the HLA-DQ2 genotype. 7 , 8 Unravelling which is the cause or the consequence, as well as the mechanisms that favor the colonization of certain bacterial groups and the co-exclusion of others should be investigated in future studies.…”

“…7 PCR amplification reactions were carried out in a 50 μl volume containing 10 mM Tris-HCl (pH 8.3), 1.5 mM MgCl 2 , 1 μM of each primer, 0.5 μM of each deoxynucleoside triphosphates, 2.5 U of Taq polymerase (Ecotaq, Ecogen, Spain), and 50 ng of DNA. The amplification products were subjected to gel electrophoresis in 1% agarose gels stained with ethidium bromide.…”

“…5 , 6 Associations have also been established between the HLA-DQ2/DQ8 genotype and the gut microbiota composition, suggesting that the microbiota could also act as a predisposing factor for CD. 7 , 8 Early viral and bacterial infections have been associated with the subsequent development of CD. 9 , 10 A population-based cohort study estimated that children who suffered from more than ten episodes of respiratory or gastrointestinal infections presented a higher risk of developing CD compared to children with less than four infection events.…”